340 intake decisons nightmares

[71chally416]

   Just block the heat and put it back on if you're gonna run the stock exhaust and cam.

[mikerallye]

I did this same swap(stock iron for an Air-Gap) a few years back when my '73 340 was stock internally. It really didn't make a huge difference. It had better low end snap. I had to use an AVS carb(TQ wouldn't fit without a spacer) that was on the smallish side. These motors('72-'73 340's) have such low compression, nothing really helps. In reality, the stock iron spreadbore intake and TQ carb are pretty good. I never had ANY issues with heat, either. It would start easily when hot with the TQ; the AVS hated the heat. What really helps with the low-comp. 340 is a looser torque converter. Night and day difference with mine...

Mine runs strong I guess, it will leave two black marks about 100 feet and chirp the tires (727) . What will the torque converter change do? What brand and stall? thanks
The TQ is no longer available? Did you eddy boil the fuel?

[vinb]

I don't know why some of you have this boiling problem. Mine is the Weiand manifold and I do NOT have the crossover blocked. I use a 3/4" plastic carb spacer with the T-Q carb and a 160' thermo-stat, with a N-9-Y plug and the engine runs approx. only 175" in mid 90 degree weather.. If anything my engine runs to cold, when I hot lap it at the track it runs about 180-185..

[mikerallye]

I don't know why some of you have this boiling problem. Mine is the Weiand manifold and I do NOT have the crossover blocked. I use a 3/4" plastic carb spacer with the T-Q carb and a 160' thermo-stat, with a N-9-Y plug and the engine runs approx. only 175" in mid 90 degree weather.. If anything my engine runs to cold, when I hot lap it at the track it runs about 180-185..

Maybe we're onto something here: a couple posts ago bennydodge had a TQ and no heat problems either. Perhaps the TQ resists boiling whereas the aluminum body carbs have this problem. I tried everything on my 440 engine with little success and finally sold the car due to summer drivability. It is definitely a common problem. I am using a 180 thermo and NGK V power plugs, new radiator and heater core.   

[mikerallye]

  Just block the heat and put it back on if you're gonna run the stock exhaust and cam.

I would love to, if I knew that the heat problem would be solved.  The intake is off and I am trying to decide the best course of action to take. And, only do one time.

[bb71challenger]

I would think that the TQ would run cooler because it has the plastic body that tends to keep the fuel much cooler than a regular carb. TQ's are really an awesome carb, its when someone gets one way out of tune that things go south. IMO they are pretty hard to get right but once you do they are hard to beat.

[mikerallye]

My dumb     threw one away and replaced it with the eddy.   

[vinb]

T-Q's are around,  just keep looking. Make sure the throttle shafts are good and just get a carb kit and go to town. When my buddy comes back from Europe I'll see if he has any he wants to sell.

I have about 11 of them all years with bad throttle shafts, someone used to make a kit to repair them but I can't find the company.  I was told I could use a Q-Jet bushing kit? Drill them out and install new bushings, maybe CP might know.
I never had any problem tuning them, but them again that's the only carb we where allowed to use in NHRA Stock & SuperStock.

Also try using a 1/2" or 3/4" wooden spacer, Moroso & other companies have them..
that's the best for a heat problem..

[71chally416]

I totally agree the TQ is a vastly underrated carb. I saw quite a few of them on Ebay recently. The secret for a street motor is to get the dashpot adjusted right to open the secondaries smoothly.

[redelliott]

i had the same boiling fuel problem with my holley and i put on a heat shield from summit cheap and made a huge difference its just a 1/4" piece of aluinimum that covers alittle more than the bottem of the carb. try it

[Chryco Psycho]

II always block the heat crossover port with some decent quality steel so it will not burn out , never hurts on summer driven cars
 any aluminum contributes to heat upward in the engine , , alum valve cover , intakes & heads all transmit more heat under hood & can cause fuel to boil , alum carbs also soak up more heat , this is where the TQ was decent as long as the bowl didn`t crack

[Aussie Challenger]

  I'm setting up my new motor with a Weiand manifold, I like the aluminiun for heat disappation and a saving on weight. I will be doing a port match with minor clean up in the runners and below the carb. This combo will make a strong street motor with good driveability.
  I block off the cross-over and will be running an insulator/spacer to keep the heat out of the carby, hoping for at least a 1 1/2" lift, depending upon the height of the air cleaner and the cold air package I am making.
  The T/Q were designed to run cooler and as said before when they are set up properly they work very well on street cars. ( I won't be running one though unless I can get more access to a better range of needles )   

[solarguy]

I had the same fuel boiling problem in my 340 with 625 AFB. on a stock iron manifold.  A 1/2" phenolic 4 hole spacer solved the problem.  My car runs cool, but in hot S FLA weather and summer blended gas, it was always a fight.  I would block the heat crossover and try the spacer first. 

[mikerallye]

I had the same fuel boiling problem in my 340 with 625 AFB. on a stock iron manifold.  A 1/2" phenolic 4 hole spacer solved the problem.  My car runs cool, but in hot S FLA weather and summer blended gas, it was always a fight.  I would block the heat crossover and try the spacer first. 

I am going with this suggestion first, seems like if it works in FL it will work anywhere. thanks

[bennydodge]

Mine runs strong I guess, it will leave two black marks about 100 feet and chirp the tires (727) . What will the torque converter change do? What brand and stall? thanks
The TQ is no longer available? Did you eddy boil the fuel?

Well, when mine was stock it wouldn't leave 100ft of rubber. Maybe it's the elevation I'm at(5300ft). I put a converter in from a local shop here and it would flash to around 2500rpm's if you floored it from a standstill; with the factory converter it wouldn't even flash to more than 1300rpm's. Throttle response was REAL snappy. I still have my original TQ, nobody makes 'em, but their not that tough to find. Set up right, a TQ is tough to beat. The AVS I had was an original Carter piece, came off a '71 Imperial. Fuel woudn't boil, but it didn't start well in the heat. Make sure your radiator isn't cored, use a fan shroud and a thermostatic clutch(for the fan) and you shouldn't have any problems..